Atomic Force Microscopy Investigation of DNA Extracted from the Vegetative Forms and the Viable but Nonculturable Forms ofMycoplasma gallisepticumS6

Recent studies show that mycoplasmas have various programs of life. This means that changes in morphology and genome expression may occur once the environment of these microorganisms becomes extremely altered. In this article, we report on changes in the DNA molecule obtained from the vegetative forms and the viable but nonculturable (VBNC) forms of Mycoplasma gallisepticum S6. Atomic force microscopy studies show that the above-mentioned forms of the mycoplasma have different values of DNA parameters (height: 0.461 +/- 0.141 and 0.236 +/- 0.069 nm; width: 2.221 +/- 0.286 and 1.291 +/- 0.705 nm for the vegetative and the VBNC forms, respectively). We suppose that the observed phenomenon may be connected with the process of adaptation of these bacteria to severe environments.